34results about How to "Reduce DC component" patented technology

An embodiment of the invention is a scalable single stage differential power converter. The inverter can be implemented in signal, split and multi-phases. A multiphase converter can be achieved with only three modules. Integrated magnetics used in preferred embodiments of the invention mitigate the DC component of the steady-state dynamics and can be extended to AC ripple mitigation. Control architectures in preferred embodiments can mitigate higher order harmonics in steady state dynamics. Embodiments of the invention also provide scalability for voltage and current source topologies.

The invention provides a micro spherical type short coherent point diffraction interference measurement system and method and belongs to the micro spherical type detection technical field. The micro spherical type short coherent point diffraction interference measurement system and method aims at solving the problems that the contrast ratio of the interference field of the existing short coherent point diffraction interference measurement method is poor and accordingly the measurement accuracy is affected. The micro spherical type short coherent point diffraction interference measurement system comprises a short coherent laser, a first half lambda wave plate, a rectangular reflecting mirror, a polarization splitting prism, a first pyramid prism, a first plane mirror, a second pyramid prism, a PZT (Piezoelectric Ceramic Transducer) phase shifter, a delay platform, a second half lambda wave plate, an optical fiber coupling mirror, a single-mode polarization-maintaining optical fiber, a convergent lens, a pinhole lens, a first collimating lens, a quarter lambda wave plate, a micro-objective, a second plane mirror, a second collimating lens, a polaroid, an area array CCD (Charge Coupled Device) and a computer. According to the micro spherical type short coherent point diffraction interference measurement method, an optical path structure that the quarter lambda wave plate is combined with the polaroid is adopted to select beams in the interference field and accordingly direct current components in the beams are reduced, the contrast ratio of interference fringes is improved, and the adjustable optimization of the contrast ratio is implemented. The micro spherical type short coherent point diffraction interference measurement system and method is applied to the micro spherical type detection.

The invention discloses a built-in hybrid excitation bilateral magnetic channel linear motor and relates to the technical field of linear motors. The linear motor includes a bilateral secondary stator and a primary mover arranged between the stators, the primary mover includes 6 primary mover units, there is a magnetic barrier between the primary mover units, and the mover The sub-unit includes two H-shaped magnetic cores, the bridge arms of the H-shaped magnetic cores are provided with built-in permanent magnets, and the two ends of the primary mover unit are respectively provided with two sets of armature winding installation slots and a A set of excitation winding installation slots; the secondary stator includes a stator yoke and secondary teeth; the bilateral secondary stator is a fixed part, the primary mover is a moving part, and the primary mover is made in the middle of the bilateral secondary stator Linear motion, which constitutes a linear motion motor with a double-sided plate structure. The linear motor has the advantages of low manufacturing cost, symmetrical flux linkage structure, small DC component, small harmonic component, high thrust density and the like.

The invention discloses a dual buck full-bridge grid-connected inverter based on frequency multiplication modulation, the dual buck full-bridge grid-connected inverter comprises a power switch tube S5, wherein a drain of the power switch tube S5 is connected with a positive electrode of direct current voltage Udc, and a source of the S5 is respectively connected with the drain of a power switch tube S1, a negative electrode of a diode D2, the drain of a power switch tube S3 and the negative electrode of a diode D4. For the inverter provided by the invention, frequency multiplication modulationis used on the aspect of control, under the premise of constant switching frequency, working frequency is improved to double of the original frequency, thus, higher output voltage frequency can be obtained and grid-connected electrical energy quality is improved; isolation between an alternating current side and a direct current side is realized structurally, and direct current component of the grid-connected voltage is reduced; moreover, the switch tube is in a half-cycle working mode, thus, switch loss is reduced, continuing current circuit grid-connected current does not pass through a body diode which has relatively poor performance, so, the dual buck full-bridge grid-connected inverter has the advantages of low grid current total harmonic distortion and high reliability.

The application discloses a synchronized phasor measurement method, system and related components, including: collecting power signals, adding the absolute time scale output by the 5G clock to the power signals; obtaining the amplitude-frequency response curve of the power signal; determining the power signal according to the amplitude-frequency response curve The state of the power signal, the state includes an attenuated DC component, and / or contains an interharmonic component or a harmonic component, and / or contains an amplitude modulation signal and / or a phase angle modulation signal; the power signal is calculated by an algorithm corresponding to the state The fundamental phasor parameters of . This application uses 5G with superior communication performance such as short delay, high reliability, high-precision time synchronization, and extremely high bandwidth for data transmission and time synchronization, which can meet the requirements of the distribution network synchrophasor measurement device for transmission. The delay requirement saves the input of GPS and optical fiber and other communication inputs, thereby saving the cost of synchrophasor measurement devices, high measurement accuracy, and improving the application effect of advanced applications of wide-area measurement, control and protection of distribution networks.

The method includes steps: using sub band mapping to map modulation symbols to pointed sub band for transmission; next, through IDFT transform to form signal of multiple sub bands (MSB) in time domain (TD); then, through phase shifting and periodic expand to form signal of MSB with shifted frequency and expanded cycle in TD; carrying out waveform shaping and frequency spectrum shaping signal of MSB in TD; finally; using shifted overlap carries out waveform multiplexing in TD for shaped waveform symbol so as to form transmission symbol. The receiver of the filter set in MSB divides up the received data sequence into multiple data blocks, and each data block is equal to length of prototype filter; and then, carries out operations including waveform matching, phase shafting, DFT etc for the data block so as to obtain data symbol transmitted on pointed sub band. The invention can implement transmitting and receiving signal of multicarrier transmission system based on filter set in MSB.

This disclosure provides a synchronized phasor measurement method and system for anti-attenuation DC component interference, which performs full-wave discrete Fourier transform on the signal to be measured, and then extracts four half-wave discrete Fourier transforms from the calculation process Result; based on the extracted four half-wave discrete Fourier transform results, the error caused by the attenuated DC component in the phasor measurement result is calculated, and the error is removed; the traditional discrete Fourier transform method based on the discrete Fourier transform can be solved when the power system fails. The synchrophasor measurement algorithm of Lie transform cannot deal with the problem of attenuated DC component in the fault signal.

The invention discloses an excitation power circuit of a rotary transformer, belongs to the field of drive power sources, and solves the problems of complex circuit and incapability of independently working in the traditional excitation power of the rotary transformer. The excitation power circuit consists of a sinusoidal oscillation circuit, an amplitude adjusting circuit and a power amplifying circuit, wherein the sinusoidal oscillation circuit consists of a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C1, a capacitor C2, a capacitor CSEL1, a capacitor CSEL2, a first operational amplifier and a second operational amplifier; the amplitude adjusting circuit consists of a resistor R6, a resistor R7, a resistor RSEL, a capacitor C3 and a third operational amplifier; and the power amplifying circuit comprises a resistor R8 and a power amplifier. The frequency of a sinusoidal excitation power source generated by the circuit of the invention is modulated by selecting a capacitance value of the capacitor CSEL1 and the capacitor CSEL2, and the amplitude value of the sinusoidal excitation power source is adjusted by changing the resistance value of the resistor RSEL. The excitation power circuit of the invention serves as the drive power source of the rotary transformer.

The invention discloses a distributed optical fiber sensing system based on differential amplification technology. It consists of two parts: optical path detection and circuit demodulation; the optical path uses two microwave signals of different frequencies to modulate onto the signal light: the frequency of one microwave signal is within the Brillouin frequency shift frequency, and the frequency of the other microwave signal is higher than that of the Brillouin frequency shift. The deep frequency shift frequency is slightly lower; on the circuit, a power divider is used to separate the two signals, filter and demodulate them separately, and then perform differential amplification to amplify the demodulated signal. The differential amplification structure is used to amplify the signal collected by the data acquisition card in a specific amplitude range, which solves the problem that the upper computer data acquisition card range is limited in the distributed Brillouin time domain analysis sensor system, and the DC component is large. Time cannot meet the accuracy of data collection, which leads to the problem that the accuracy of system measurement is reduced. The device of the invention works stably, and can accurately measure the temperature (or stress) change position and temperature value (or stress value) in multiple measurements.

A method for measuring fault distance of power transmission line measures A phase voltage Uma, current Ima, load current Ifa, zero sequence fault component ImaO, unit positive sequence, zero sequence induction and resistance at M side of fault point then substitutes above values into formula of KL = ( LO - L1 ) L1 and formula of KR = ( RO - R1 ) R 1 for calculating out result.

The invention discloses a detection device and a detection method for carbon monoxide concentration. In the detection device, a first beam splitter splits a light beam emitted by a light source into acalibration light beam and a detection light beam; the calibration light beam is irradiated to a photoelectric detector after passing through a collimator and a calibrated absorption cell to obtain acalibrated electrical signal; a second beam splitter splits the detection light beam into a reference light beam and a measurement light beam; the reference light beam is irradiated to the photoelectric detector after passing through the collimator to obtain a reference electrical signal; the measurement light beam is emitted from the center of a Fresnel lens after passing through the collimatorand is irradiated to a reflecting end after passing through a to-be-detected area, and the reflecting end reflects the light beam to the photoelectric detector from an original path to obtain a measurement electrical signal; a differential amplifier performs differential operation on the reference electrical signal and the measurement electrical signal to obtain a differential signal; a processordetermines the carbon monoxide concentration in the to-be-detected area according to the calibration electrical signal, the reference electrical signal and the differential signal. The detection device and the detection method disclosed by the invention can improve the detection accuracy of laser spectrum measurement of the carbon monoxide concentration in an open area.

The invention provides a direct current component control method and system used for a three-phase or single-phase inverter, wherein the method used for the three-phase inverter comprises the following steps: detecting the output voltage and direct-current component of the three-phase inverter; carrying out conversion from static coordinates to rotational coordinates on the direct current component so as to obtain a component of the direct current component on the rotational coordinates; calculating a direct voltage adjusted value according to the component of the direct current component on the rotational coordinates and a direct current voltage given value, and calculating the voltage given value according to the direct voltage adjusted value and a reference output voltage; calculating the output regulation voltage of the three-phase inverter according to the voltage given value and the output voltage of the three-phase inverter, and carrying out conversion from the rotational coordinates to the static coordinates on the output regulation voltage of the of the three-phase inverter and carrying out PWM (pulse-width modulation) so as to obtain driving signals of the three-phase inverter; and carrying out driving control on the three-phase inverter according to the driving signals. The method and system provided by the invention can be used for effectively reducing the direct-current component in the output voltage of the inverter so as to adapt to load requirements.